WO2000055495A1

WO2000055495A1 - Fuel feed pump

Info

Publication number: WO2000055495A1
Application number: PCT/JP1999/001317
Authority: WO
Inventors: Kunihiko Takao; Isao Hayase; Yuuzou Kadomukai; Hiroyuki Yamada
Original assignee: Hitachi, Ltd.
Priority date: 1999-03-17
Filing date: 1999-03-17
Publication date: 2000-09-21

Abstract

A fuel feed pump capable of compactly forming a fuel pressurizing means, reducing a contact load at an area where a rotating power is converted to a reciprocating one, and changing a contacting form to a surface contact so as to provide high efficiency and reliability, wherein an oscillating cylinder and an oscillating piston are combined with each other so as to form a crank pin drive, a spring for pressing the piston against a cam in an intake stroke is eliminated, and an intake path is formed in a crank pin and the oscillating piston so as to provide an action as an intake valve to open and close a communication between the crank pin intake path and the piston intake path.

Description

Specification

Fuel supply pump

Technical field

The present invention relates to a pump for supplying fuel to a fuel injection valve of an internal combustion engine, and more particularly to a fuel supply pump for pumping fuel to a high pressure.

Background art

As a conventional high-pressure fuel supply pump, for example, there is a single cylinder plunger type as described in Japanese Patent Application Laid-Open No. H8-14140. In this high-pressure fuel supply pump, a cylinder is attached to a head cover which is a part of an engine housing, and a plunger is reciprocally and slidably fitted in the cylinder. The lower end of the plunger is connected to a tut, which is pressed against the cam surface by a return spring and is in sliding contact with the cam. Therefore, when the cam is rotated by the rotation of the camshaft, the plunger is reciprocated through the tappet, and the fuel in the fuel pressurizing chamber is pressurized and supplied to the injection valve (injector) through the discharge valve and the common rail. You.

The above-described high-pressure fuel supply pump has the following technical problems because it employs a force-driven system as a reciprocating mechanism of the plunger.

This is a problem of reliability and friction loss related to sliding of the cam and the tap due to the spring force of the return spring provided to press the plunger against the cam surface during the suction stroke. That is, in the compression stroke, the force acting in the direction of pushing down the plunger due to the fuel pressure in the fuel pressurizing chamber and the spring force of the return spring act on the tut and the cam surface. The spring force of the return spring needs to be large so that the tut does not separate from the cam surface even when the camshaft rotates at high speed, and as a result, the contact load increases. Also, since the contact form between the tip and the cam surface is a line contact, it is difficult to achieve fluid lubrication, and the surface pressure increases, and the reliability of the cam and the stick, especially the Reliability is a problem.

Further, since the cam outer periphery is long and the above-mentioned contact load is large, friction loss between the pad and the cam surface increases (mechanical efficiency decreases).

As means for solving the above problems, for example, as described in JP-A-64-73166, the lower end of the plunger is connected to a valve seat, and this valve seat is connected to the slider by a return spring. It is imposed. The slider has a cam roller, and the cam roller comes into sliding contact with the cam. Therefore, friction loss and reliability are improved because the cam roller is in rolling contact with the cam surface.However, since there is a return spring, The contact load is still working. In addition, in this conventional technique, components such as a slider and a roller are added, and new problems such as a longer pump body in the axial direction of the plunger arise.

Disclosure of the invention

An object of the present invention is to provide a fuel supply pump having high mechanical efficiency and high reliability by configuring a compact fuel supply pump and reducing frictional force by reducing the force acting on the plunger (piston) during the compression process. It is to provide a supply pump. In order to achieve the above object, a fuel supply pump according to the present invention includes a supply passage for supplying fuel, a discharge passage for discharging fuel to an injection valve side, and a booster for increasing fuel pressure between the supply passage and the discharge passage. And a swing piston that swings with the swing cylinder and reciprocates in the swing cylinder while swinging with the swing cylinder. It is composed of:

According to the present invention, the fuel supply pump can be made compact by combining the oscillating cylinder and the oscillating biston for crank pin drive, and the spring for pressing the piston against the cam during the suction stroke can be eliminated. Accordingly, in the compression step, the force of the spring does not act on the piston, so that the friction loss can be reduced.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing a fuel supply pump according to one embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a fuel injection system using the present embodiment.

FIG. 3 is a sectional view of a fuel supply pump according to another embodiment of the present invention. FIG. 4 is a cross-sectional view of a fuel supply pump according to another embodiment of the present invention, which is the same as FIG.

FIG. 5 is a diagram showing a cross section and a system configuration of a fuel supply pump according to another embodiment of the present invention.

FIG. 6 is a diagram showing a cross section and a system configuration of a fuel supply pump according to another embodiment of the present invention.

FIG. 7 is a view showing a cross section of a fuel supply pump according to another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a fuel supply pump according to an embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of a fuel injection system using the present embodiment.

As shown in FIG. 1, a pump body 21 is fixed to a casing 20. The pump body 21 has a fuel supply passage 22, a discharge passage 23, and a pump chamber. The fuel supply passage 22 and the discharge passage 23 are provided with a suction valve 25 and a discharge valve 26, respectively. The discharge valve 26 is a holding member 26 c which holds a ball valve 26 a, a valve seat 26 b, and a ball valve 26 a slidably in the discharge passage 23. A spring 26d for urging the ball valve 26a and the holding member 26c in the direction of the valve seat 26b, a supporting member 2 supporting the valve seat 26b and forming a fuel passage in the center thereof. 6e, which is a check valve that restricts the fuel flow direction. On the other hand, the suction valve 25 is composed of a valve body 25a, a valve seat 25b, a spring 25c for urging the valve body 25a in a direction opposite to that of the discharge valve, and a holding member 25d. As with the discharge valve 26, it is a check valve that restricts the fuel flow direction.

The solenoid valve 27 is fitted into the pump body 21, and an engagement member 28 and a spring 29 are provided inside the solenoid valve 27. When the solenoid valve 27 is turned off, an urging force is applied to the engagement member 28 in a direction to open the suction valve 25 by the spring 29. Since the biasing force of the spring 29 is greater than the biasing force of the spring 25c of the suction valve 25, when the solenoid valve 27 is OFF, the suction valve 5 is in the open state as shown in Fig. 1. Has become.

The pump main body 21 is formed with a spherical support portion 30 that opens to the pump chamber 24. A swing cylinder 31 is fitted to the spherical support portion 30, and a spherical support member 32 is provided. The pump body 21 is swingably connected to the pump body 21. A pressure chamber 34 is provided on the head side of the swing piston 33 of the swing cylinder 31. The pressurizing chamber 34 and the pump chamber 24 communicate with each other via a communication passage 35 provided at the tip of the oscillating cylinder 31. Here, the opening area of the pump chamber 24 on the side of the communication passage 35 is formed to be smaller than the cross-sectional area of the sliding bore portion 31a. Further, an escape groove 36 is provided at an end of the sliding bore portion 31a on the communication passage 35 side.

The oscillating piston 33 is formed integrally with a piston portion 33a that slides in a sliding bore portion 31a of the oscillating cylinder 31 and a ring portion 33b that transmits rotational power. The ring portion 33b is, for example, an eccentric shaft center of a crankshaft 37 (a valve camshaft may be a crankshaft 37) connected to a valve camshaft for opening and closing an intake / exhaust valve (not shown). It slides freely on the crank pin part 38 having

In FIG. 2, an engine (not shown) is provided with an injection valve 2 corresponding to a combustion chamber of each cylinder, and fuel is injected from the injection valve 2 to the engine (not shown) for injection control. Controlled by ON-OFF of solenoid valve (not shown). The injection valve 2 is connected to a common rail 3 common to the cylinders, and while the injection control solenoid valve (not shown) is open, the fuel in the common rail 3 is sent from the injection valve 2 to the engine (not shown). ). Therefore, the common rail 3 continuously corresponds to the fuel injection pressure. It is necessary to accumulate a high predetermined pressure. For this purpose, the high-pressure fuel supply pump 1 is connected via the supply pipe 4. The high-pressure fuel supply pump 1 of the present embodiment operates as a variable discharge type high-pressure fuel supply pump.

The high-pressure fuel supply pump 1 regulates the pressure of the fuel from a fuel tank 5 to a constant pressure by a known low-pressure fuel supply pump 6 and a pressure regulator 7, and controls the pressure of the sucked fuel to a high level. In addition, a relief valve 9 is provided between the suction pipe 8 of the high-pressure fuel supply pump 1 and the common rail 3, and is opened when the pressure in the common rail 3 exceeds a predetermined value. To prevent damage.

The electronic control unit (ECU) 10 that controls this system receives information on the number of revolutions and load from, for example, a sensor 11 that detects the engine revolution and a sensor 12 that detects the load. The ECU 10 outputs a control signal to an injection control solenoid valve (not shown) so that the optimum injection timing and injection amount are determined according to the engine operation state and the like determined as described above. At the same time, the ECU 10 outputs a control signal to the high-pressure fuel supply pump 1 so that the fuel injection pressure becomes an optimum value according to the rotation speed and the load.

More preferably, a pressure sensor 13 for detecting the pressure in the common rail 3 is installed on the common rail 3 so that the signal of the pressure sensor 13 becomes an optimum value set in advance according to the engine speed and load. The discharge amount of the high-pressure fuel supply pump 1 is controlled during the operation.

Next, the operation of the high-pressure fuel supply pump 1 will be described.

In FIG. 1, the crank pin 37 having an eccentric shaft center rotates with respect to the shaft center of the crank shaft 37 with the rotation of the crankshaft 37, so that the ring of the oscillating piston 33 is formed. The part 33 b rotates and slides with respect to the crank pin part 38, and the piston part 33 a reciprocates in the sliding bore part 31 a of the swing cylinder 31. At this time, the driving cylinder 31 swings with respect to the pump body 21 by the spherical support portion 30 and the spherical support member 32. Therefore, the piston part 33a reciprocates while sliding in the sliding bore part 31a of the swing cylinder 31.

When the oscillating piston 33 moves from the top dead center to the bottom dead center (fuel intake stroke), the solenoid valve 27 is not energized (at the time of OFF). The engaging member 28 is engaged with the suction valve 25, and the suction valve 25 is opened. Therefore, the low-pressure fuel flows into the pump chamber 24 through the fuel inlet 22 a and the fuel supply passage 22 and the suction valve 25, and is further supplied to the pressurizing chamber 34. At this time, the discharge valve 26 is closed.

When the oscillating piston 3 3 moves from the bottom dead center to the top dead center (fuel pressurization / discharge stroke), first, when the solenoid valve 27 is not energized (OFF), the pump chamber 24 Since the pressure is maintained at a low pressure almost equal to that of the fuel inlet port 2 2a, the discharge valve 2 6 cannot be opened and the suction valve 25 is open, so the fuel that has flowed into the pressurizing chamber 34 is pumped by the pump chamber 24, the suction valve 25, the fuel supply passage 22 and the fuel. It is returned to the suction side pipe 8 through the suction port 22a.

Next, when the solenoid valve 27 is energized (ON), an electromagnetic force greater than the urging force of the spring 29 is generated, and the engaging member 28 is pulled toward the solenoid valve 27 side. Material 28 and suction valve 25 are separated. Then, the valve body 25a comes into contact with the valve seat 25b by the urging force of the spring 25c, so that the suction valve 25 is closed. As a result, the pressurization of the fuel in the pressurizing chamber 34 by the oscillating piston 33 starts, and the fuel pressure in the pressurizing chamber 34 and the pump chamber 24 increases with the spring 26 d of the discharge valve 26. When the power is overcome, the ball valve 26a separates from the valve seat 26b, and the discharge valve 26 is opened to discharge the pressurized fuel gas in the pressurizing chamber 34 and the pump chamber 24. It is discharged to the common rail 3 through the passage 23 and the supply pipe 4.

In this way, in the process in which the oscillating piston 33 moves from the bottom dead center to the top dead center, the timing of energizing the solenoid valve 27 and the energizing period are controlled to reduce the amount of fuel discharged to the common rail. Can be controlled.

In the high-pressure fuel supply pump according to the present embodiment, a crankpin drive system is used as the power of the crankshaft 37, so that the cam drive system does not require a return spring that must be provided. In other words, the rotational power of the crank pin 38 is supported by the ring portion 33b of the oscillating piston, and the two form a sliding bearing. Therefore, the contact load between the crank pin 38 and the ring portion 33b of the oscillating biston can be significantly reduced, and the contact form between the two can be a surface contact, so that fluid lubrication is easily established. Become.

The opening area on the communication passage 35 side of the pump chamber 24 provided at the tip of the oscillating cylinder 31 is provided at the side end of the sliding bore 31 a of the oscillating cylinder 31. Since the sectional area is smaller than that of the groove 36, the spherical portion of the swing cylinder 31 is always pressed against the spherical support portion 30 of the pump body 21 by the internal pressure of the pressurizing chamber 34. Therefore, the spherical portion of the oscillating cylinder 31 and the spherical support portion 30 are in close contact with each other, so that leakage of high-pressure fuel between the two can be prevented.

Furthermore, since the means for pressurizing the fuel by the combination of the oscillating cylinder and the oscillating piston is adopted, in the conventional cam drive system, the side pressure generated between the cylinder and the piston during the pressurizing process can be made almost zero. Therefore, the sliding loss between the cylinder and the piston is reduced, and the reliability at the same portion is improved. Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a cross-sectional view of the fuel supply pump showing a suction step and FIG. 4 shows a pressurization / discharge step. Here, compared to the embodiment shown in FIG. Those with numbers have the same function.

A feature of the present embodiment is that a suction passage is formed to reach the pressurizing chamber 34 through the crankshaft 37, the crankpin 38, and the swing piston 33. That is, a crankshaft suction passage 40 is formed in the axial direction near the center of the shaft of the crankshaft 37, and the crankpin 38 is connected to the crankpin 38 so as to communicate with the crankshaft suction passage 40. A passage 41 is provided. The crankpin intake passage 41 is formed over substantially half of the periphery of the crank section of the crankpin. On the other hand, a piston piston passage 33 is provided in the center of the piston portion 33a of the oscillating piston 33, and one end thereof communicates with the crankpin suction passage 41 only during a suction stroke. The ends communicate with the pressure chambers 34, respectively. Here, although not shown, it goes without saying that the crankshaft suction passage 40 communicates with the suction side pipe 8. Next, the operation of the present embodiment will be described. In FIG. 3, during the suction stroke, the low pressure fuel flows into the pressurizing chamber 34 via the crankshaft suction passage 40 because the crankpin suction passage 41 communicates with the biston suction passage 39. I do. At this time, since the solenoid valve 27 is not energized (at the time of OFF), the suction valve 25 is opened, and at the same time, the low-pressure fuel is supplied to the fuel suction port 22 a and the fuel supply passage 22. Then, the gas flows into the pump chamber 24 via the suction valve 25, and is further supplied to the pressurizing chamber 34.

In FIG. 4, during the pressurization / discharge stroke, the communication between the crankpin suction passage 41 and the piston suction passage 39 is cut off by the crankpin 38, so that the communication between the crankpin suction passage 41 and the crankshaft suction passage 40 is performed. The supply of low-pressure fuel is stopped. Accordingly, since the crankpin suction passage 41, the pressurizing chamber 34 and the pump chamber 24 are closed spaces, pressurization is started by the driving piston 33. At this time, when the solenoid valve 27 is not energized (OFF), the discharge valve 26 is closed and the suction valve 25 is open. The fuel is returned to the suction side pipe 8 through the suction valve 25, the fuel supply passage 22, and the fuel suction port 22a. Also, when the solenoid valve 27 is energized (ON), the suction valve 25 is closed, so fuel pressurization is started and the discharge valve 26 is opened, and the discharge passage 23 and supply Discharged to common rail 3 via pipe 4.

As described above, the crank pin 38 not only functions to transmit the rotational power to the swing piston 33 but also functions as a suction valve that opens and closes the communication between the crank pin suction passage 41 and the piston suction passage 39. Has both.

In the high-pressure fuel supply pump 1 of the present embodiment, since the piston suction passage 39 is formed in the piston portion 33 a of the oscillating piston 33, the oscillating piston is increased by an amount obtained by multiplying the passage area by the pressure. 33 The load acting on the head can be reduced. Also, the crank pin 38 is connected to the crank pin suction passage 41 and the piston suction port. Since it functions as a suction valve for opening and closing the communication of the entrance passage 39, the suction valve is not required, and the fuel suction efficiency is increased.

In the embodiment described above, the shape of the head, which is the center of swing of the swing cylinder, is a spherical shape. However, the present invention is not limited to this shape. Good. Also, an electromagnetic valve that engages an engaging member having an urging force to hold the intake valve in the opening direction and controls the opening and closing of the intake valve with the operation timing of the actuator has been described. However, the present invention is not limited to this. For example, the above-described effects can be obtained even when a solenoid valve is directly attached to the actuator and the solenoid valve closes the suction passage when the solenoid valve is closed. Can be demonstrated.

Also in the present embodiment, the high-pressure fuel supply pump 1 operates as a variable discharge rate type.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing a cross section of the fuel supply pump and a system configuration. Here, components denoted by the same reference numerals as those of the embodiment shown in FIGS. 1 and 2 perform the same operation. The casing 20 fixed to the pump body 21 is omitted.

A feature of the present embodiment is that a check valve is used as the suction valve 42 and a pressure adjusting valve 14 is provided to adjust the pressure in the common rail. That is, a suction valve 42 is provided in each of the fuel supply passages 22 communicating with the suction-side piping 8. The suction valve 42 includes a ball member 42 a, a valve seat 42 b, and a holding member 42 c that holds the ball valve 42 a so as to be able to reciprocate in the fuel supply passage 22. It is composed of a spring 42d that urges the ball valve 42a and the holding member 42c in the direction of the valve seat 42b, and serves as a check valve that restricts the fuel flow direction. The common rail 3 is provided with a pressure regulating valve 14, which is opened when the pressure in the common rail 3 exceeds a predetermined value, and is connected to a fuel tank (not shown) via a pipe 15. It is configured to return. Therefore, in this case, the relief valve 9 shown in FIG. 2 becomes unnecessary.

Next, the operation of the present embodiment will be described. During the suction stroke, the suction valve 42 opens, so low-pressure fuel flows into the pump chamber 24 through the suction pipe 8, the fuel supply passage 22, and the suction valve 25, and It is supplied to the pressurizing chamber 34. At this time, the discharge valve 26 is closed. When the swing piston 33 moves from the bottom dead center to the top dead center, the suction valve 42 is closed, so that the fuel in the pressurizing chamber 34 is pressurized by the swing piston 33. Starts, and when the fuel pressure in the pressurizing chamber 34 and the pump chamber 24 overcomes the urging force of the spring 26 d of the discharge valve 26, the ball valve 26 a moves away from the valve seat 26 b. Then, the discharge valve 26 is opened, and the pressurized fuel in the pressurizing chamber 34 and the pump chamber 24 flows into the discharge passage 23 and the supply pipe 4. Through the common rail 3. The pressure in the common rail 3 is adjusted and maintained at a certain set value by the pressure adjustment valve 14

In the high-pressure fuel supply pump and the fuel supply system using the same according to the present embodiment, the solenoid valve does not need to be used, so that the size of the pump body can be reduced, and the pressure in the common rail 3 can be reduced by the pressure regulating valve. It can be adjusted and maintained at a certain set value.

In the present embodiment, the high-pressure fuel supply pump 1 operates as a fixed discharge rate type.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a cross section of the fuel supply pump and a system configuration. Here, components having the same reference numerals as those in the embodiment shown in FIGS. 3, 4 and 2 perform the same operation. The casing 20 fixed to the pump body 21 is omitted.

The feature of the present embodiment is that the suction valve and the check valve are eliminated, and a pressure regulating valve 14 is provided to regulate the pressure in the common rail. In other words, the pump chamber 24 formed in the pump body 21 includes a crankshaft suction passage 40 formed near the center of the crankshaft 37 and a crankpin suction passage 41 provided in the crankpin 38. Although not shown, the oscillating piston 33 communicates with the suction side pipe 8 through a piston suction passage 39 and a pressurizing chamber 34 formed in the center of the piston portion 33a. The pump chamber 24 communicates with the common rail 3 via a discharge valve 42 having a check valve function, a discharge passage 23 and a supply pipe 4. The common rail 3 is provided with a pressure regulating valve 14. When the pressure in the common rail 3 exceeds a predetermined value, the valve is opened and a fuel tank (not shown) is connected via a pipe 15. It is configured to return to.

With the above configuration, the solenoid valve and the suction valve do not need to be used, so that the pump body can be further reduced in size and size, and the pressure in the common rail 3 is adjusted to a certain set value by the pressure regulating valve. · Can be maintained.

In the embodiment described above, the system configuration in which the common rail 3 is provided with the pressure regulating valve 14 is described. However, the present invention is not limited to this. As shown in Fig. 2, a relief valve 9 is provided between the suction pipe 8 of the high-pressure fuel supply pump 1 and the common rail 3 so that the high-pressure fuel supply pump can be used as a fixed displacement. Can also be applied, and the effects described above can be exerted.

In the present embodiment, the high-pressure fuel supply pump 1 operates as a fixed discharge rate type. Next, another embodiment of the present invention will be described with reference to FIG. Fig. 7 FIG. 3 is a diagram showing a cross section of a fuel supply pump. Here, components denoted by the same reference numerals as those of the embodiment shown in FIG. 1 perform the same operation. The casing 20 fixed to the pump body 21 is omitted.

The feature of the present embodiment relates to a method of connecting the spherical portion of the oscillating cylinder 31 and the spherical support portion 30 formed on the pump body 21. That is, as shown in the enlarged view (part A) of FIG. 7, the pump body 21 is provided with a housing 21a having a ring-shaped recess 21b. A flange 21c is formed at the end of the driving piston 33 on the side of the piston. On the other hand, the support ring 43 is made of an elastic material, and is composed of a spherical portion 43a and an engagement portion 43b in a ring shape so that the cylindrical portion of the swing cylinder 31 is inserted. Some of them are notched (not shown).

Therefore, the support ring 43 is inserted into the oscillating cylinder 31 via a notch (not shown) of the support ring 43, and the spherical portion of the oscillating cylinder 31 is attached to the spherical surface of the pump body 21. When the support ring 43 is pushed in while being pressed against the support part 30, the spherical part 43a of the support ring 43 comes into contact with the spherical part of the swing cylinder 31 and the engaging part 4 3b is fitted into the recess 21b, and the engaging portion 43b is engaged with the collar 21c, whereby the swing cylinder 31 is freely movably connected to the pump body 21. .

With the above configuration, the swing cylinder 31 can be swingably fitted to the pump body 21 with a simple configuration and reliably.

In the present embodiment, the swing cylinder 31 and the pump body 21 are connected by the support ring 43. However, the present invention is not limited to this. It is also possible to employ a method such as plastic coupling or caulking in which the parts are plastically flowed and fitted.

In the present embodiment, the high-pressure fuel supply pump 1 operates as a variable discharge rate type.

According to each of the above-described embodiments, the fuel supply pump can be made compact by combining the oscillating cylinder and the oscillating piston to perform crank pin driving, and the spring for pressing the piston against the cam during the suction stroke is eliminated. At the same time, the force acting on the piston by the pressure of the pressurized fuel can be reduced to reduce the friction loss. In addition, since a suction passage is formed in the crankpin and the oscillating piston, it also acts as a suction valve that opens and closes the communication between the crankpin suction passage and the biston suction passage. Efficiency increases. Furthermore, since the contact form at the portion where the rotational power is changed to reciprocating motion can be surface contact, fluid lubrication is easily achieved, and a highly efficient and reliable fuel supply pump can be obtained.

Claims

The scope of the claims

1. A fuel supply pump comprising: a supply passage for supplying fuel; a passage for discharging fuel to the injection valve side at a predetermined pressure; and means for increasing the pressure of fuel between the supply passage and the discharge passage. The pressure raising means is constituted by a swing cylinder that swings with its head as a swing center, and a swing piston that reciprocates in the swing cylinder while swinging together with the swing cylinder. Fuel supply pump.

2. A supply passage for supplying fuel, a passage for discharging fuel to the injection valve side, means for increasing the pressure of the fuel between the supply passage and the discharge passage, and opening the discharge passage at a predetermined pressure. A fuel supply pump having a discharge valve that performs a reciprocating motion in the oscillating cylinder while oscillating with the oscillating cylinder, the oscillating cylinder being oscillated about the head thereof. A fuel supply pump comprising a moving oscillating piston.

3. A supply passage for supplying fuel, a passage for discharging fuel to the injection valve side, means for increasing the pressure of fuel between the supply passage and the discharge passage, and opening the discharge passage at a predetermined pressure. A fuel supply pump provided with a discharge side valve that performs the above operation. The fuel pump includes a crankpin eccentric to a drive shaft, a swing piston rotatably engaged with the crankpin, and an inner wall. The fuel supply is characterized in that a sliding bore portion is formed to slidably support the oscillating biston, and the head is constituted by an oscillating cylinder having a spherical portion or a cylindrical surface portion serving as an oscillating center. pump.

4. A supply passage for supplying fuel, a passage for discharging fuel to the injection valve side, means for increasing the pressure of the fuel between the supply passage and the discharge passage, and opening the discharge passage at a predetermined pressure. A fuel supply pump provided with a discharge valve that performs a reciprocating motion in the oscillating cylinder while oscillating together with the oscillating cylinder. A fuel supply pump comprising a oscillating piston, wherein a suction passage is provided inside the oscillating piston as at least a part of the supply passage.

5. A supply passage for supplying fuel, a passage for discharging fuel to the injection valve side, means for increasing the pressure of the fuel between the supply passage and the discharge passage, and opening the discharge passage at a predetermined pressure. A fuel supply pump provided with a discharge valve that rotates the crankshaft eccentrically with respect to a drive shaft; a swing piston that rotatably engages with the crankpin; and a swing piston that is rotatable on an inner wall. A slidable bore portion is formed to slidably support the oscillating cylinder. The oscillating cylinder has a spherical surface portion or a cylindrical surface portion as a oscillating center in a head portion, and at least a part of the supply passage. A fuel supply pump, wherein a suction passage is provided inside the oscillating piston.

6. The pressurizing chamber is located on the head side of the oscillating piston inside the sliding bore of the oscillating cylinder. A communication passage communicating the pressurizing chamber and the discharge passage is opened on a fixed wall surface with which the head of the oscillating cylinder abuts during the oscillating movement, and an opening area of the communication passage is defined by the oscillating cylinder. 6. The fuel supply pump according to claim 1, wherein a sectional area of the sliding bore is smaller than that of the sliding bore.

7. The fuel supply pump according to claim 1, wherein a relief groove is provided at a tip of a sliding bore of the swing cylinder.

8. The fuel supply pump according to claim 1, wherein a suction valve is provided in the supply passage, and the suction valve is opened and closed by the actuator.

9. The fuel supply pump according to claim 1, wherein a suction valve is provided in the supply passage, and the suction valve is opened and closed by a pressure difference between before and after the suction valve.

10. The fuel supply pump according to claim 1, wherein a suction valve that opens and closes according to a pressure difference between the front and rear of the valve is provided in the supply passage, and a pressure adjustment valve is provided in the discharge passage.

11. The fuel supply pump according to claim 4, wherein a pressure regulating valve is provided in the discharge passage.

1 2. A common rail that accumulates pressurized fuel, an injection nozzle that injects fuel in the common rail into each cylinder of the internal combustion engine, and intermittently injects fuel in response to electric signals, and a supply passage that supplies fuel A passage that discharges fuel to a common rail; a discharge valve that opens the discharge passage at a predetermined pressure; and a passage that communicates the supply passage and the discharge passage. An electromagnetic valve that communicates with the discharge passage, a swing cylinder that swings around its head as a swing center, and a pivot piston that reciprocates in the swing cylinder while swinging with the swing cylinder. A fuel supply pump comprising: